Method and apparatus for directional skin tightening

ABSTRACT

A cosmetic method of directionally tightening human skin tissue includes providing an ablative laser source and a non-ablative laser source, then using the ablative laser source to form one or more overlapping circular shaped microchannels in the skin tissue; the overlapping microchannels formed have a longitudinal dimension larger than their cross dimension; then, using the non-ablative laser source to weld the microchannels, whereby the welding causes the skin tissue to tighten.

RELATED APPLICATION

This application is related to and claims priority to U.S. provisionalapplication Ser. No. 62/291,796, filed Feb. 5, 2016, the entire contentsof which are herein incorporated by reference.

BACKGROUND

Present day non-invasive skin tightening techniques only deliver small,millimeters of improvement. By contrast, in an invasive procedure, suchas a facelift, typically larger, centimeters of improvement areexperienced. Directional skin tightening is commonly known in that onecan shape the skin with a skin compression technique in which the skinwould generally be expected to hold its shape.

SUMMARY OF THE PRESENT INVENTION

Herein it is suggested achieving directional shrinkage of the skin bycombining two different mechanism of actions induced by two laserssources: an ablative laser (such as, for example, an Erbium laserworking at a wavelength of about 2.9 μm (about 2940 nm) or a CO2 laserworking at wavelength of about 10.6 μm (about 10,600 nm)) withsubsequent application of heating through a non-ablative laser (such as,for example, a laser operating at about a range of wavelengths fromabout 1400 nm to about 1,565 nm). The idea behind the concept is inducea sequence of fractional ablative holes in skin using the ablativelaser, to compress the holes, thus reducing the linear dimension of theskin in the direction of the compression, which will subsequently bewelded closed by the non-ablative laser and then held or otherwisemaintained in place in this reduced dimension for the duration of thehealing process, thus providing a directional tightening effect. Inaddition to light energy in the above wavelengths for the non-ablativeheating, other methods may be used, such as RF energy or another lightenergy source which selectively absorbs water or hemoglobin atsub-ablative energy dosages. Other light-based wavelengths include:500-600 nm, 980-2000 nm or Intense Pulsed Light (IPL) energy filtered tocorrespond to the foregoing wavelengths.

In an aspect, a cosmetic method of directionally tightening human skintissue includes: (a) providing an ablative laser source and anon-ablative laser source; (b) using the ablative laser source to formone or more overlapping circular shaped microchannels in the skintissue; the overlapping microchannels formed having a longitudinaldimension larger than their cross dimension; and (b) using thenon-ablative laser source to weld the microchannels, whereby the weldingcauses the skin tissue to tighten.

In another aspect, the cosmetic method further includes the step ofsqueezing or stretching the skin tissue in a longitudinal direction orin a cross direction or both. In the present cosmetic method, step (b)takes place before step (c) or step (c) takes place before step (b) orthe sequence of steps is: (c) followed by (b) followed by (c). Further,the step of squeezing or stretching is performed before step (b) or thestep of squeezing or stretching is performed after step (b) or the stepof squeezing or stretching is performed after step (c).

In a further aspect, the step of squeezing or stretching is performedwith a mechanical squeezer or stretcher. The skin tissue may be held ina squeezed or stretched condition for a period of time sufficient toweld the microchannels. The cosmetic method may further include the stepof providing an isotropic or anisotropic polymer sheet, placing thesheet on the skin tissue surface; performing step (b) and then step (c)such that the polymer sheet shrinks one of isotropically oranisotropically. In an alternative embodiment, the skin tissue istreated with the ablative then the non-ablative laser(s) and, oncewelded, the polymer sheet is placed over the skin tissue for a period oftime to maintain the position for sufficient time to assure that theweld “takes”.

In yet another aspect, a cosmetic method of directionally tighteninghuman skin tissue includes: providing an ablative laser source and anon-ablative laser source; using the ablative laser source to form oneor more microchannels in the skin tissue; using the non-ablative lasersource to weld the microchannels, whereby the welding causes the skintissue to tighten in the cross direction. It may include the furtherstep of squeezing or stretching the skin tissue in the cross direction.

In yet a further aspect, the method of the present invention, thewavelength of the ablative laser may be about 10,600 nm or about 2940 nmand the wavelength of the non-ablative laser may range from about1400-1565 nm.

In another aspect, in the cosmetic method, the mechanical squeezer orstretcher comprises a body portion, the body portion having a pluralityof arms, wherein the arms have end portions which are movable towardsand away from one another, further comprising the steps of contactingthe skin tissue with the end portions of the arms and manipulating theend portions in contact with the skin tissue to either move towards oneanother or move away from one another, thereby either squeezing orstretching the skin tissue. The mechanical squeezer or stretcher may bemounted on the distal portion of a laser device

In a further aspect, the skin tissue treated is one or more wrinkles orother imperfections and the step of squeezing or stretching is acrossthe one or more wrinkles or other imperfections along the long axis ofthe one or more wrinkles or other imperfections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (A-D) illustrates the steps in the formation of weldedmicrochannels in the present invention.

FIG. 2 illustrates one method by which oval-shaped microchannels areproduced in the present invention.

FIG. 3 illustrates photographically the results of a study to implementthe method of operating the dual laser sources in the present invention.

FIG. 4 illustrates photographically the results of a study to implementthe method of operating the dual laser sources of the present invention.

FIG. 5 illustrates photographically the welding of microchannels formedin accordance with the present invention.

FIGS. 6 and 7 illustrate cross-sectional and top views respectively ofablated microchannels.

FIG. 8 illustrates compressed and welded micro-cuts.

FIG. 9A to 9D illustrate the application of a flat sheet over the areato be treated and the treatment steps.

FIGS. 10A, 10B, 10C and 10D illustrate an exemplary mechanical devicefor either compressing the skin or stretching the skin before, duringand/or after a procedure in accordance with the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The welding discussed above may be achieved in a directional manner, byway of example only, by an operator physically pushing, squeezing orotherwise manipulating the skin in one direction of an array offractional ablated holes, and then applying the second laser source toweld and hold this shape, as may be see in FIG. 1. Several studies haveshown that laser assisted tissue bonding (LTB) offers a fast andefficient method for full-thickness macroscopic incision closure, whichdiminishes scar formation. Examples in the literature include thefollowing:

-   -   Fried N M, Walsh J T Jr. Laser skin welding: in vivo tensile        strength and wound healing results. Lasers Surg Med. 2000;        27(1):55-65; Simhon D, Halpern M, Brosh T, Vasilyev T, Ravid A,        Tennenbaum T, Nevo Z, Katzir A. Immediate tight welding of skin        incisions using an innovative temperature-controlled laser        soldering device: in vivo study in porcine skin. Ann Surg. 2007        February; 245 (2):206-13; Ahmed A. Abbood Human Skin Wound        Welding Using 980 nm Diode Laser: an in Vitro Experimental        Study. Iraqi J. Laser, Part B, Vol. 11, pp. 9-20 (2012)

While traditional full-thickness macroscopic incisions are characterizedby the full separation of opposing tissue from both sides of the cut andleaving a macroscopic void volume between them, LTB may be basicallysubdivided into 2 main sub-phases differing in their mechanism ofaction: 1) photochemical tissue bonding (PTB) and 2) photothermal tissuebonding. The latter can be further subdivided into 2 different aspects:laser tissue welding (LTW) and laser tissue soldering (LTS). LTW refersto the introduction of concentrated laser energy to the opposed woundmargins that causes their initial liquefaction, followed by fusion ofthe two edges, whereas LTS uses an additional component known as a“solder” (see above references). The present invention generally relatesto the LTW type of mechanism in order to directionally tighten the skinin the desired shape.

In connection with fractional laser skin treatment, which is an aspectof the present invention, a study was made to evaluate the feasibilityof directional skin tightening, using the fractional ablative CO2 laser(10,600 nm) and subsequently the non-ablative laser (1,565 nm) on freshharvested porcine skin (ex-vivo model). Porcine skin is highly similarto the skin anatomy and physiology of humans.

This study was designed to prove the concept of inducing directionalskin tightening by combining two lasers sources, working in differentmechanisms of action, welding the holes closed in the compresseddirection.

The experimental setups evaluated by this study are described in Table 1below:

TABLE 1 Description of laser setups Setup Ablative laser (10 μm)Non-ablative laser (1,565 nm) 1 SuperPulse ResurFX (M22) & scannerAcuScan 120 DeepFX No sapphire (without topical cooling) 10 mj Pulse E:30 mj 10 × 10 mm at density of 10% Pulse width: 2.5 ms Expected diameterof ablative 10 × 10 mm at density of 450/cm² zone: 120 μm Expecteddiameter of coagulative zone: 100 μm This setup was evaluated in singleand double-pass 2 SuperPulse ResurFX (M22) & free fiber (no scanner)AcuScan 120 DeepFX No sapphire (without topical cooling) 10 mj Pulse E:13 W 10 × 10 mm at density of 10% Pulse width: continuous 10 s all overthe whole area Expected diameter of ablative Expected diameter ofcoagulative zone: 100 μm zone: 120 μm This setup was evaluated in singleand double-pass

The study was designed to evaluate the histological effect of combinedtreatments of ablative and non-ablative laser energies to inducedirectional skin tightening effects. The treatment included thefollowing three steps: (1) Fractional ablative treatment with a CO2laser. (2) The treated area was then manually squeezed in the desireddirection and held in that position until completion of step (3). (3)The squeezed/compressed tissue was welded with the non-ablative laser.

In this in-vivo study, fractional oval holes were ablated and evaluated.One technique to create such oval holes is to closely space theformation of the (normally) circular holes or microchannels so that theedges of one hole overlap in a longitudinal direction with the hole orholes immediately preceding it, as can be seen in FIG. 2. Othertechniques of ablating elongated microchannels or compressing circularmicroscopic channels to make them oval are known in U.S. Pat. No.7,942,153 and US application No. 2015/0150629 respectively.

However, in the present invention, the combinational use of a fractionalablative laser followed by applying directional force across the patternof fractional holes and a non-ablative laser is utilized to form andthen weld the microchannels in a required orientation. For example,single microchannels of a 120 μm diameter may be combined to produce anelongated “micro-cut” that is approximately 300 um in length, again asmay be seen in FIG. 2. In addition, a guiding mechanism may be employedunder the control of a suitable programmable controller which“remembers” the positions of the microchannels and directs thenon-ablative laser to those microchannels or in the vicinity of thosemicrochannels. In an alternative arrangement, the non-ablative laser maynot be directed to the microchannels, as above, but rather may beactivated in the general area in which the microchannels were formed.

The elongated microchannels or micro-cuts (as they hereinafter may bereferred to) discussed above may be, of course of any length, width,depth, or orientation suitable for the particular application. Forexample, a plurality of elongated micro-cuts may be arranged with theirlong axes in parallel with one another or may be arranged randomly withrespect to one another. Also, the long axes may be positioned on theskin tissue surface parallel to, for example, the long axis of a wrinkleor wrinkles or may be positioned perpendicular to the long axis of awrinkle or wrinkles. In a treatment of facial imperfections, theelongated micro-cuts may vary greatly in their direction and orientationwith respect to one another and with respect to skin surface wrinklesand other imperfections. Microchannels may be any pattern of discretecircular holes distributed homogeneously or non-homogenously, partiallyoverlapped or without any overlap, on a skin area where a directionalforce or a directional tightening is required such as, for example,along a wrinkle to be stretched so as to cause the wrinkle to completelyor mostly disappear.

The purpose of the directional compression is to close the void causedby the ablation, bringing the margins of the micro-cuts together priorto their welding. The direction of the compression may be in anyorientation relative to the elongated micro-cuts, along its short orlong axis (such as shown in FIGS. 1A-D) or along the short axis (notshown) in order to achieve different desired effects.

The capability of directional tissue welding using a non-ablativecoagulative laser source which followed the forming of an ablatedfractional pattern and its directional compression, demonstrated thatthe margins of the micro-cuts were attached to each other. Known in theprior art is the use of non-ablative laser directed into ablated holesto coagulate the content therein in order to reduce the hole depth andhealing time. This technique is disclosed, for example, in USapplication no. 20150202007. Directional compressing and directionalwelding of the margins of micro-cuts in order to achieve directionalskin tightening are aspects of the present invention.

Treatments with the ablative laser in these experiments resulted inablative holes with a diameter of ˜120 μm. This could be detected byboth binocular microscopy and histologically. FIGS. 3 and 4 illustratehistological comparisons between ablative only treatments and combinedtreatments of ablating-squeezing-welding. The upper two rows 1 and 2 ineach of FIGS. 3 and 4 provide perpendicular cross-section views of theskin sample and the lower two rows provide a horizontal cross-sectionview at a depth of up to 60 μm from sample skin surface.

After compression of the skin tissue, the goal was to apply thenon-ablative laser to the compressed lesions to perform the welding ofthe lesion closed. An attempt at a high density exposure was thought toinsure a higher probability to align with many of the ablated lesionsand an additional set up attempted to expose the area with a large spotfiber over the entire surface area for a completely confluent treatmentmaking sure to expose over the ablated lesions.

As can be seen in FIG. 3 and in FIG. 4, the margins of the ablated zoneswere surrounded by a thin rim of coagulation area marked with singlearrows. Ablated areas are marked in the figures with double arrows. Incontrast to the macro voids created by full thickness macroscopicincision mentioned above which can be welded or soldered according tothe prior art, fractional ablated microchannels provide micro-reservoirsto hold and contain secretions from adjacent tissues such as, forexample, capillary blood or extracellular fluid as well as cellularfluid originating from ruptured cells along the margins of the holes.

These fluid components contain, at least partially, proteinic materialand chromophores such as hemoglobin. Therefore, the bonding of themicrochannels or micro-cuts by a non-ablative laser may be a combinationof LTB, LTW and LTS. The amount of fluid secreted into a micro-cut is afunction, among other things, of the internal holes' surface. Due to thefractional nature of the ablative step in this directional tighteningtreatment, the area of a microchannel surface over the microchannelvolume is much higher than in the case of a full thickness incision.Moreover, a full thickness incision does not form a closed containerwhich may hold and contain fluids from adjacent tissue or alternativelymay create an overflow of bleeding should a blood vessel be cut.Therefore, the microchannel diameter of the ablated holes may beselected by the user to affect the amount of fluid to be secreted intothe holes. The Thermal Affected Zone (TAZ) created along the margins ofthe ablated holes may be controlled by the user as disclosed in USapplication No. 2011077627 which is incorporated herein by reference inits entirety. A thicker TAZ may reduce the amount of fluid accumulatedin a microchannel while a thinner TAZ may allow more fluid to be drainedthrough the thinner coagulated area.

Referring now to FIG. 5, this figure provides a top view of a skinsurface treatment of the present invention under binocular microscopy.Part A represents the result right after ablation with a CO2 laser.Parts B and C represent results following an additional non-ablativetreatment, performed in one pass with a 1565 nm laser. Part D is similarto Parts B and C, but with two passes of the non-ablative laser. Thenon-welded (“unsealed” as marked in the photographs) holes are seen andmay be expected as the non-ablative laser was applied with the ablationzone randomly.

Referring now to FIG. 6, that figure shows a skin cross section 60having ablated microchannels 61 and intact tissue areas 62 between them.Areas 63 are part of the microchannel's internal surfaces shown in thiscross section. Skin cross section 60 defines a fractionated incisionplane, perpendicular to skin surface, having a length L and a height H.A fractionated incision plane consists of ablated strips defined byablated microchannels 61 and the intact tissue areas 62 between them.Another aspect of the present invention is a method to create at leastone fractionated incision plane using an ablative fractional laser, andthen compressing the at least one fractionated incision plane with amechanical force F which is approximately perpendicular to thefractionated incision plane, as seen in FIG. 7 from a top view, to closemicrochannels 70. This is followed by providing targeted non-ablativelaser spots 71 which are configured to bond together the compressedsides of at least some of microchannels 70.

In addition, multiple parallel fractionated incision planes may becreated across the skin. Welding a microchannel having a diameter of D,for example, creates a displacement of about D/2 of tissue from eachside across the bonding line 72. Therefore, by creating multiplefractionated incision planes one can obtain accumulated directionaltightening proportional to the product of D/2 and number of planes. Thelength of bonding line 72 is proportional to the product of π and themicrochannel diameter. Once the external mechanical force F is removedafter bonding, bonded microchannels 71 tighten the skin along line A-A.At the same time, counterforces Fc acting on bonding lines 72 in adirection tend to reopen the bonded microchannels. The present inventionprovides bonding strength sufficient to overcome the load encountered bycounter force Fc. The fractionated incision plane is characterized,among other things, by the ratio of the length of bonding lines 72 overintact lines 73 across line B-B. The larger this ratio is, the higherthe counter force Fc and the stronger the bonding force required.

Referring now to FIG. 8, compressed and welded ablative fractional holes81 are illustrated. These holes were bonded by targeting non-ablativelaser spots 82. Since a non-ablative laser may cause local tightening, anon-ablative spot 83 located in-between welded microchannels 84 mayre-open these welded microchannels. Therefore, the present inventionprovides a laser system for directional skin tightening which isconfigured to laser the non-ablative laser mainly on and in the vicinityto the ablated microchannels to avoid the reopening of bondedmicrochannels. Due to the same phenomena of local tightening due tonon-ablative irradiation, another aspect of the invention is to ablatemicrochannels 84 between coagulated areas 82 as “strain releasers” forwelded microchannels 81. In order to achieve directional tighteningalong specific directions, and at varying amounts across a largersurface for a desired cosmetic effect, not all of the ablated fractionalmicrochannels may need to be bonded by the non-ablative laser.Non-homogeneous or discrete distribution of welding spots may targetonly a subset of a microchannel fractional pattern. Moreover, thecompression step for compressing an ablated fractional pattern ofmicrochannels may compress all or only a subset set of the ablatedmicrochannels pattern while the welding step again may target only asubset of the compressed microchannels. When the coagulative laseroperating at a wavelength of 1,565 nm was applied alone, onlycoagulative zones could be histologically observed. U.S. applicationSer. No. 13/038,773, filed Mar. 2, 2011, which discloses variouscombinations of ablative and non-ablative laser treatments which may beuseful in combination with the present invention, is incorporated hereinby reference in its entirety.

Applying the coagulative laser in clinical setup 2 above (at 30 mj)immediately following the ablative treatment resulted in detected closedholes. Although tissue welding was seen to occur following a double passof the coagulative laser, a single pass appeared to achieve the sameresult. Since the scanned coagulative laser on skin surface wasperformed randomly, a few ablated, non-welded holes could be detected asnot all area was covered homogeneously by the non-ablative coagulativelaser in the evaluated scanning setups.

When free fiber treatment of the coagulative laser was used to weld theablated tissue, tissue welding was achieved, as detected by bothmethodologies, that is, under the binocular microscopy as well ashistologically.

The potential of providing a dual wavelength treatment in order toachieve directional tightening was successfully proven in the abovestudy. As seen in the ex-vivo study shown in FIG. 5, round-shapedablative zones created by CO2 laser have mostly been welded by thesubsequent treatment of the non-ablative laser (1,565 nm). Not allablative zones were welded as the non-ablative energy was randomlydistributed over the ablative-treated areas, however, the tendency oftissue welding could be clearly observed. The ablative zones weresignificantly closed, especially in the deeper parts of evaporatedareas. This phenomenon could be seen in both the perpendicular sectionsand horizontal sections of the in-vivo study of FIG. 3. This effectoccurred immediately following treatment procedure. Similar positiveresults were seen when the non-ablative laser was applied to ablativezones using energy levels of 10 mj and 20 mj as seen in FIG. 3. Energylevels of 30 mj were found to be not desirable due to safety concernswhen applied to the ablative zone.

While the above discussion has been directed to the use of a CO2 laser,it is to be understood that the present invention is not so limited andother suitable laser sources may be employed depending on desiredeffects and results. For example, a YAG laser which may be more ablativeand less coagulative than a CO2 laser may be employed to create themicrochannels.

Clearly, other sequences of application of the ablative laser and thenon-ablative laser may be envisioned, as the present invention is notlimited to a sequence of ablate/squeeze/non-ablate (a/k/a heat). Forexample, the sequence may be squeeze/ablate/heat or ablate/heat/squeezeor heat/ablate/heat/squeeze or any other permutation of the factors ofablating, squeezing and heating.

While, as may be seen in FIG. 1, the ablated/treated area may besqueezed “by hand”, the present invention also envisions othermethodologies to achieve this squeezing or compressing. One example is amechanical device that compresses/squeezes the skin tissue to leave theoperator's hands free to operate the laser device doing the ablationand/or heating. This may be a freestanding device (like a pair oftweezers or tongs) or may be a device attached to the distal portion ofthe laser device itself, so that in one motion the skin tissue isapproached, the tongs squeeze the skin tissue either before or afterfiring of the ablative laser pulse(s) in any desired order. Whiletreating only small areas at a time, say approximately 1 cm squares, andwith a degree of tightening within this square controlled by the densityof the lesions, with higher density providing more tightening, with theimmediate effect of the welding, this can be applied to an as neededlocation, with a real time impact on directional tightening. While theabove discusses squeezing or compressing using tweezers or tongs, it isenvisioned that an opposing motion—stretching—is also within the purviewof the present invention, and is discussed below.

Turning now to FIGS. 10A through 10D, these figures illustrate anexemplary mechanism which may be used to either compress the skin tissueor stretch it (or even both). In FIG. 10A, the mechanism 1002 includes atapered body 1003 (although the body portion may not be tapered) onwhich is mounted two pivoted arms 1004 and 1005. Although two arms areshown it is to be understood that any number may be employed. The arms1004 and 1005 are pivoted at points 1008 and 1007 and biased by springs1006 and 1009. When, by way of example only, pressure is placed ondepressions 1012 and 1014 against the action of the springs, the armswill pivot about points 1008 and 1007 and the ends 1010 and 1016 of thearms will move in an outward direction.

Turning now to FIG. 10B, the mechanism 1002 of FIG. 10A is shown mountedon laser device 1020. It is to be understood that the laser device willbe activated and fire along axis and in direction 1022 towards skintissue surface 1024. In FIG. 10B, the arms 1004 and 1005 are shown intheir closed or non-extended positions for this illustration. Turningnow to FIG. 10C, this figure shows the arms 1004 and 1005 in theposition after the arms have been depressed in directions 1026 and 1028.As can be seen, the ends 1010 and 1016 of the arms have moved indirections 1030 and 1032 along the skin tissue surface 1024.

This, from the above arrangement, it can be seen that two actions may becontemplated. First, the mechanism may contact the skin tissue when thearms are in the position shown in FIG. 10C, and then the act ofdepressing in directions 1026 and 1028 stopped, which will cause thearms to move to the position of FIG. 10A. This action will cause anyskin tissue situated between ends 1010 and 1016 to be squeezed orcompressed. This action may occur before, during or after activation ofthe ablative and/or non-ablative laser(s).

In a second arrangement, the mechanism may contact the skin tissue inthe position shown in FIG. 10B and the arms then depressed to move themto the position shown in FIG. 10C while in contact with the skin tissue.This will cause the skin tissue to be stretched in directions 1030 and1032. This action also may occur before, during or after activation ofthe ablative and/or non-ablative laser(s).

In order that the skin tissue be adequately contacted and gripped foreither compressing or stretching, the ends 1010 and 1016 of the arms mayhave serrations 1040 and 1042 as seen in FIG. 10D to better grip andmanipulate the tissue. The body 1003 shown in FIG. 10A may be solid orof a skeleton-like framework and may be of a clear or an opaquematerial. It may also be of a permanent-type or disposable material.

A programmed controller may be employed in the apparatus and method ofthe present invention to control the positioning and the operation ofthe ablative and the non-ablative lasers, the positioning of thenon-ablative laser after the operation of the ablative laser asdiscussed above, and even the movement of the arms 1004 and 1005. Thecontroller may include a display and a user interface, as conventionallyemployed in cosmetic laser devices, to facilitate the operation of thedevice.

Another methodology for squeezing the skin is to apply a flat sheet ontothe skin tissue to be treated as shown in FIGS. 9A to 9D. The materialof the flat sheet may be, by way of example, of polymer and may beeither isotropic or anisotropic. When heat is applied to the polymersheet it will tend to shrink in its length and width dimensions, eitheruniformly (in the case of an isotropic polymer) or non-uniformly (in thecase of an anisotropic polymer). This shrinkage will cause anymicrochannels ablated in a previous step to move from a round hole toclosed, oval holes. The sequence of events is illustrated in FIGS. 9athrough 9D. The choice of an isotropic or anisotropic polymer allows theability to directionally tighten the skin tissue as desired for theparticular treatment regimen. It is also envisioned that the flat sheetmay be placed onto the patient's skin tissue, the ablative laser causedto fire through the flat sheet to ablate microchannels and then anon-ablative laser applied to cause shrinkage of the sheet and thusclosing of the ablated microchannels.

As an alternative, instead of a sheet which may compress the skin tissuein one or more directions, a flat sheet may be employed to simply holdor maintain the tissue in its condition after a procedure during whichthe skin was compressed (or for that matter stretched) by either manualcompression or stretching or manipulation of the skin tissue through themechanical device of FIGS. 10A through 10D.

In addition, once the ablation/heating steps have occurred as describedabove, in order to accelerate the “welding” of the microchannels shut, acold compress or cooled surface may be pressed onto the treated site.

The tendency of tissue welding with non-ablative laser was seen alsowhen applied to the line-shape ablative zones. These results were seenin both, perpendicular and horizontal sections. However, onlynon-ablative energy level of 10 mj was safe when it was applied to theline-shape ablation, when 20 mj was considered to be inappropriate forreasons of safety.

The initial feasibility study to create ablated zones and then adherethe margins by using a non-ablative laser was successfully achieved.

In addition, the ability to weld the skin tissue of a several hundredmicrons incision has a higher successful potential than welding of deepand long incisions.

What we claim is:
 1. A cosmetic method of directionally tightening humanskin tissue comprising: (a) providing an ablative laser source and anon-ablative laser source; (b) using the ablative laser source to form aplurality of overlapping circular shaped microchannels in the skintissue; the overlapping microchannels formed having a longitudinaldimension larger than their cross dimension; and, (c) using thenon-ablative laser source to weld the microchannels, whereby the weldingcauses the skin tissue to tighten in one or more directions.
 2. Thecosmetic method of claim 1, further comprising the step of squeezing orstretching the skin tissue in the one or more directions across aportion of the skin tissue treated or along a portion of the skin tissuetreated.
 3. The cosmetic method of claim 2, wherein the step ofsqueezing or stretching is performed before step (b).
 4. The cosmeticmethod of claim 2, wherein the step of squeezing or stretching isperformed after step (b).
 5. The cosmetic method of claim 4, wherein theskin tissue is held in a squeezed condition for a period of timesufficient to weld the microchannels.
 6. The cosmetic method of claim 2,wherein the step of squeezing or stretching is performed with amechanical squeezer or stretcher.
 7. The cosmetic method of claim 6,wherein the mechanical squeezer or stretcher comprises a body portion,the body portion having a plurality of arms, wherein the arms have endportions which are movable towards and away from one another, furthercomprising the steps of contacting the skin tissue with the end portionsof the arms and manipulating the end portions in contact with the skintissue to either move towards one another or move away from one another,thereby either squeezing or stretching the skin tissue.
 8. The cosmeticmethod of claim 7, further comprising the step of mounting themechanical squeezer or stretcher on a laser device.
 9. The cosmeticmethod of claim 2, wherein the skin tissue treated is one or morewrinkles and the step of squeezing or stretching is across the one ormore wrinkles or along the long axis of the one or more wrinkles orboth.
 10. The cosmetic method of claim 1, wherein step (b) takes placebefore step (c).
 11. The cosmetic method of claim 1, wherein step (c)takes place before step (b).
 12. The cosmetic method of claim 1, whereinthe sequence of steps is: (c) followed by (b) followed by (c).
 13. Thecosmetic method of claim 1, wherein the step of squeezing or stretchingis performed after step (c).
 14. The cosmetic method of claim 1, furthercomprising the step of providing an isotropic or anisotropic polymersheet, placing the sheet on the skin tissue surface; performing step (b)and then step (c) such that the polymer sheet shrinks one ofisotropically or anisotropically.
 15. The cosmetic method of claim 1,wherein the wavelength of the ablative laser is about 10,600 nm or about2940 nm.
 16. The cosmetic method of claim 1, wherein the wavelength ofthe non-ablative laser ranges from about 1400-1565 nm.